Department of Environmental Science, Policy and Management, 137 Mulford Hall #3114, University of California, Berkeley, Berkeley, CA 94720-3114, USA.
Mol Ecol. 2009 Mar;18(5):997-1005. doi: 10.1111/j.1365-294X.2008.04056.x. Epub 2009 Jan 21.
Ants are some of the most abundant and ecologically successful terrestrial organisms, and invasive ants rank among the most damaging invasive species. The Argentine ant is a particularly well-studied invader, in part because of the extreme social structure of introduced populations, known as unicoloniality. Unicolonial ants form geographically vast supercolonies, within which territorial behaviour and intraspecific aggression are absent. Because the extreme social structure of introduced populations arises from the widespread acceptance of conspecifics, understanding how this colonymate recognition occurs is key to explaining their success as invaders. Here, we present analyses of Argentine ant recognition cues (cuticular hydrocarbons) and population genetic characteristics from 25 sites across four continents and the Hawaiian Islands. By examining both hydrocarbon profiles and microsatellite genotypes in the same individual ants, we show that native and introduced populations differ in several respects. Both individual workers and groups of nestmates in the introduced range possess less diverse chemical profiles than ants in the native range. As previous studies have reported, we also find that introduced populations possess much lower levels of genetic diversity than populations in the native range. Interestingly, the largest supercolonies on several continents are strikingly similar to each other, suggesting that they arose from a shared introduction pathway. This high similarity suggests that these geographically far-flung ants may still recognize and accept each other as colonymates, thus representing distant nodes of a single, widely distributed supercolony. These findings shed light on the behaviour and sociality of these unicolonial invaders, and pose new questions about the history and origins of introduced populations.
蚂蚁是地球上数量最多、生态最成功的生物之一，而入侵蚂蚁则是最具破坏性的入侵物种之一。阿根廷蚂蚁是一种特别受研究的入侵物种，部分原因是其引入种群的极端社会结构，称为单巢居性。单巢居蚂蚁形成了地理上非常庞大的超级蚁群，在这种超级蚁群中，领土行为和种内侵略行为都不存在。由于引入种群的极端社会结构源于对同种个体的广泛接受，因此了解这种殖民地识别是如何发生的，对于解释它们作为入侵物种的成功至关重要。在这里，我们对来自四大洲和夏威夷群岛的 25 个地点的阿根廷蚁识别线索（表皮碳氢化合物）和种群遗传特征进行了分析。通过在同一只蚂蚁中同时检查碳氢化合物图谱和微卫星基因型，我们发现了本地和引入种群在几个方面的差异。在引入范围内，无论是单个工蚁还是巢群中的蚁群，其化学图谱的多样性都比本地种群的要少。正如之前的研究报告的那样，我们还发现引入种群的遗传多样性远低于本地种群。有趣的是，几个大洲的最大超级蚁群彼此之间惊人地相似，这表明它们来自共同的引入途径。这种高度相似性表明，这些地理上相距遥远的蚂蚁可能仍然相互识别并接受对方作为殖民地，从而代表了一个单一的、广泛分布的超级蚁群的遥远节点。这些发现揭示了这些单巢居入侵蚂蚁的行为和社会性，并对引入种群的历史和起源提出了新的问题。
